Synthesis of Pyrazine-Bridged Dinitramine Explosives with High Stability and Low Sensitivity

A novel skeleton of triazole bridged with pyrazine was constructed through the cyclization reaction of pyrazine carboxylic acid and 1,3-diaminoguanidine monohydrochloride. Based on this skeleton, dinitramine compounds N,N′-(pyrazine-2,5-diylbis(5-amino-4H-1,2,4-triazole-3,4-diyl))dinitramide (4) and N-((Z)-5-(5-((E)-5-(nitroimino)-4,5-dihydro-1H-1,2,4-triazol-3-yl)pyrazin-2-yl)-2,4-dihydro-3H-1,2,4-triazol-3-ylidene)nitramide (8) were synthesized in excellent yields (88% and 89%, respectively). Compared with C–C bridged compounds A and diazo bridged compounds B, the thermal stability of dinitramine compounds 4 (Td = 202 °C) and 8 (Td = 212 °C) linked by a pyrazine bridge was increased by 18 and 29 °C, respectively. And pyrazine bridged dinitramine compounds 4 (Dv = 8313 m·s–1, IS = 25 J, FS = 240 N) and 8 (Dv = 8380 m·s–1, IS = 30 J, FS = 288 N) exhibit acceptable detonation performance and low sensitivity. This research result compensates for the mismatch between the sensitivity and energy of dinitramine compounds, providing new ideas for the development of novel dinitramide explosives with higher thermal stability.